This invention relates to certain novel hydantoin derivatives and to their use as stabilizers for synthetic polymers and provides processes for their preparation. More specifically, it is concerned with compounds having two or three hydantoin residues.
Certain classes of hydantoin derivatives are known to be useful stabilizers for synthetic polymers; such derivatives are disclosed in, for example, U.S. Pat. Nos. 3,542,729, 3,639,409, 3,705,126, 3,898,303, 3,941,744 and 3,975,462, Japanese Patent Application No. 49-72332, as laid open to public inspection, and German Offenlegungsschrift No. 2,623,464.
However, these known stabilizers have a number of disadvantages. For example, some of them, in spite of being good light stabilizers, are relatively volatile and are therefore of no practical use in the stabilization of synthetic polymers since they volatilize at processing temperatures and may also volatilize during prolonged storage of the stabilized articles. Others of these compounds can easily be extracted from synthetic polymers with water or organic solvents and, again, are of little practical use for the stabilization of synthetic polymers. Though hydantoin derivatives in which, e.g. two or three 2,2,6,6-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione are linked to certain bridging member such as an alkylene group at their 3-position are known, hydantoin derivatives in which, e.g. two or three of the residues are linked to 2,2-bis[4-(2-hydroxypropoxy)phenyl]propane have not been discoved.